土肉桂與山肉桂種間嫁接之研究

Abstract

本研究利用切接及合接兩種枝接方式，以土肉桂為接穗、山肉桂為砧木進行種間嫁接，結果顯示嫁接成活率隨嫁接月份及方法有很大差異，兩種接法於3~4月時嫁接成活率最高，12~1月及5~6月嫁接成活及親和率最低，不親和徵狀則以10~12月發生率最高。 親和嫁接苗光合作用特性隨著生長期逐漸恢復正常，在3個月生時，切接、合接苗之暗呼吸率、光補償點、淨光合作用速率均不及土、山肉桂截幹苗（對照組），但至12個月生時，二者已相當接近，顯示嫁接後隨生長期延長，生理狀態逐漸恢復正常。嫁接親和及截幹苗氣孔內外二氧化碳濃度比均隨著光度增加而逐漸減少，當光度達到200μmol photon m-2 s-1 時趨緩，並固定在0.5~0.7間。親和嫁接苗之葉綠素a、b含量在接後初期提高，與截幹苗有顯著差異，但隨著生長時間增加，嫁接苗之葉綠素含量逐漸減少，至12個月生時與截幹苗已無顯著差異。合接法因切面較切接單純，因此癒傷較佳，不親和株亦較少，切接則反之。合接苗在3個月生時其外部已完全癒傷，但其輸導組織分化尚不完整，切面上仍有部份壞疽層殘留，至12個月生時輸導組織分化，已無壞疽層殘留。切接苗在3個月生時其接合部未完全癒傷，內部輸導組織亦尚未分化完全，橫切面上有明顯之壞疽層存在，至12個月生時其輸導組織雖已完全分化，但仍有部分壞疽層存在，其中部分是切穗韌皮部殘留所造成。 嫁接不親和徵狀在嫁接後陸續出現，主要為萌芽晚、生長緩慢、穗條黃化、接合部接合微弱，葉片黃化、葉脈顏色變深、葉先端枯死掉落、植株衰弱逐漸死亡等。嫁接不親和株之平均淨光合能力、暗呼吸率、葉綠素a、b及總量均明顯較其他苗木低，光補償點及光飽和點卻較高，顯示不親和嫁接苗輸導組織癒傷不完整，生理受限，植株將逐漸衰弱死亡。由切面觀察，切接不親和之壞疽層存在明顯，韌皮部組織亦明顯有扭曲及分化不良情形，合接不親和則有異常的木質部薄壁組織存在，韌皮部也分化不良。

The cut grafting method and splice grafting method were used in this study, Cinnamomum osmophloeum was used as scion and Cinnamomum insulari-montanum was used as stock in this study. The experimental results showed that the survival rate varied with the time and method of grafting, for example, from March to April, Both grafting methods had the highest survival rate; while from December to January and from May to June, both Methods yielded the lowest survival rate and compatibility; the incompatibility was highest when grafting was conducted from October to December. For the compatibility grafts, the photosynthesis characteristics returned to normal along with growing time; when it was 3-month old, the dark respiration rate, light compensation point and net photosynthesis rate of cu grafting and splice grafting were lower than those non-grafting seedlings of both C. osmophloeum and C. insulari-montanum; until they were 12-month old, the grafts and non-graft seedling become comparable, this indicated that the extended growth and back to normal state of the physiological conditions of grafts. The CO2 ratio from inside and outside of the stomata of both the compatibility grafts and non-graft seedlings decreased with increasing light intensity, when light intensity reached 200μmol photon m-2 s-1,and become stable around 0.5~0.7. For the compatibility grafts, the contents of both chlorophyll a and b increased at beginning but decreased with growing time, and there was significant difference between compatibility grafts and non-graft seedlings; the chlorophyll contents decreased with time; and there was no significant difference between compatibility grafts and non-graft seedling when they were 12-month old. Overall, the splice grafting method yielded better healing condition and less incompatibility. The vessels of cut grafts did not show sign of differentiation and necrotic layer was obvious when they were 3-month old. After 12 months, the vessels of cut grafts were completely differentiated, however, fragments of necrotic layer still existed. On the other hand, the splice grafts healed very well when they were 3-month old, although parts of necrotic layer still remained, with partially the differentiated vascular bundles. After 12 months, the vessels were differentiated with no necrotic layer. After grafting, the external characteristics of graft incompatibility showed gradually, which included late sprouting, slow growth, yellow leaf, weak tissue union, dark vein and withering leaf. For the incompatibility cut grafts, the necrotic layer was obvious and the phloem was twisted and incompletely differentiated. The incompatibility splice grafts also showed signs such as abnormal thin-wall xylem tissue and incompatibility phloem. On the average, incompatibility grafts were low in net photosynthesis rate, light compensation point, light saturation point and the amount of chlorophyll.